Mr Garrett told the program he had been “particularly strong in this book about leadership and Rudd’s leadership and I think it needed to be said”.

“Rudd wasn’t someone who was easy to work with in that way, and his vanity and his exercise of power as prime minister was contrary ultimately, to me, to what good leadership is.”

“He was [a megalomaniac]. I am not the only one to think it either.”

“So I am critical of him that’s true, I am very critical but for good reason.”

Mr Garrett also cast as risky Mr Rudd’s tendency to change his stance on issues and policy.

“His career is a series of passionate embraces of issues that he then walks away from of you know running government one way in a certain direction and then turning around and heading off in another direction a couple of days later,” Mr Garrett said.

Kevin Rudd after resigning in the House of Representatives chamber at Parliament House in Canberra.Source:The Daily Telegraph

“There was a reason that the caucus decided to remove Kevin Rudd and make Julia Gillard therefore the prime minister and its because the business of government had become impossible with him.”

Mr Garrett slammed Rudd’s “unbelievably poor” treatment of his successor, Ms Gillard, and said he felt she unfairly copped a lot of flak because of her sex.

“I don’t think Julia Gillard was ever given clear air as they say, a fair chance,” he said.

“I don’t care what anybody says if you are a reasonable, dispassionate observer of Australian media and popular culture you would have to say that she got a lot of stick for being a woman.”

Mr Garrett was elected to the House of Representatives in 2004 and when Labor was swept to power under Mr Rudd, Peter was appointed Environment Minister.

07/09/15 Professor Julia Gillard at Adelaide University. Now in her first public lecture at the University of Adelaide, Professor Gillard will explore why the quality of education is so critical to the wellbeing and sustainability of a community. Pic Roy VanDerVegt.Source:News Corp Australia

He remained at the post under Ms Gillard when she took the top job.

It was the Rudd-Gillard power shift that moved him to eventually quit in 2013.

Mr Garrett also confessed that his biggest failing in his own political career was the government’s Home Insulation Program, which caused the death of four people.

“The fact that we had the death of four young kids in the insulation scheme that the government established to deal with the Global Financial Crisis, and that was a low light in a lot of different ways,” he said.

Mr Garrett also addressed his changing story about an envelope of cash given to him by poker machine interests, saying it was actually a cheque that he returned.